1. Field of the Invention
This invention relates to a laser sputtering apparatus by which thin films are produced and a method for the production of dielectric thin films by using the laser sputtering apparatus.
2. Description of the Prior Art
FIG. 6 shows a conventional sputtering apparatus that is provided with a vacuum chamber 1. In the vacuum chamber 1 are disposed a substrate support 2 and a target holder 4, which is electrically insulated from the vacuum chamber 1 by means of an insulator 3. Argon gas is introduced into the vacuum chamber 1 through a gas inlet port 5 to keep the atmosphere in the vacuum chamber at a pressure 10.sup.-2 -10.sup.-3 Torr by means of a vacuum pump connected to an exhaust port 6. When a high frequency voltage is applied to the target holder 4 by means of a power source 7, plasma 8 is generated in a space between the substrate support 2 and the target holder 4.
When a raw material 9 of a dielectric substance is placed on the target holder 4, ions included in the plasma 8 strike the surface of the raw material 9, causing the sputtering effect to form a dielectric thin film on a substance 10 which is set on the substrate support 2.
However, most of the particles emitted from the raw material (SrTiO.sub.3, for example) are atoms or molecules, so that the dielectric thin film formed with the substrate support 2 whose surface temperature is relatively low (below 300.degree. C., for example) is amorphous and the dielectric thin film formed with the substrate support 2 whose surface temperature is relatively high (over 300.degree. C., for example) is polycrystalline. As a result, when the thickness of the dielectric thin film is 1,000 A-10,000 A, the permittivity of the dielectric film is as low as 30 -35 when it is amorphous, and the withstanding voltage of the dielectric film is low when it is polycrystalline.